[2] The county was formed on January 15, 1851, and named after Captain Edwin B. Guthrie,[3] who died in the Mexican–American War.

91.86% were non-Hispanic White, 0.34% were Black, 2.58% were Hispanic, 0.22% were Native American, 0.36% were Asian, 0.15% were Native Hawaiian or Pacific Islander and 4.50% were some other race or more than one race.

[12] At the 2000 census there were 11,353 people, 4,641 households, and 3,248 families in the county.

The racial makeup of the county was 98.61% White, 0.12% Black or African American, 0.05% Native American, 0.14% Asian, 0.04% Pacific Islander, 0.42% from other races, and 0.61% from two or more races.

Of the 4,641 households 27.90% had children under the age of 18 living with them, 60.00% were married couples living together, 6.60% had a female householder with no husband present, and 30.00% were non-families.

The population ranking of the following table is based on the 2020 census of Guthrie County.